Polyvinyl acetal resin composition containing tetrahydrofurfuryl oxalate



Patented Apr. 16, 1940 POLYVINYL ACETAL RESIN COMPOSITION CONTAINING TETRAHYDROFURFURYL OX ALATE Henry B. Smith, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application October 7, 1938,

Serial No. 233,882

8 Claims.

This invention relates to plastic compositions,

and more particularly to compositions comprising a polyvinyl acetal resin and a conditioning agent.

5 One object of. this invention is to produce compositions of matter which may be made into permanently transparent, strong and flexible sheets or films of desired thinness which are substantially waterproof, are unaffected by ordinary 1 photographic fluids and possess the desired properties of a support for sensitive photographic coatings. Another object of my invention is to produce compositions of matter which can be made into sheets suitable for use in laminated, shatter-proof glass.

produce compositions which can be rolled, ex truded, molded or otherwise worked into relatively thick sheets and massive plastics. A further object is to produce compositions suitable $0 for use in lacquers, artificial silk filaments, wrapping tissues and the like. Other objects will hereinafter appear.

I have discovered that tetrahydrofurfuryl oxalate is a very useful conditioning agent for polyvinyl acetal resins. Not only does it serve as a plasticizer in the accepted sense of the term, increasing the flexibility and toughness of polyvinyl acetal resin films, sheets, or other objects or masses containing it, but when used in amounts of about 50 or 75 or more parts per 100 parts of certain of the polyvinyl acetal resins, namely the polyvinyl acetal resins in which a predominating proportion of the acetal groups are acetaldehyde acetal groups or formaldehyde acetal groups, it has an unusual and remarkable effect which I may call elasticizing. That is to say, a sheet of polyvinyl acetaldehyde or formaldehydeacetal resin containing about -50 or 75 or, more parts of tetrahydrofurfuryl oxalate per 100 parts of resin possesses the property which, in the rubber industry, is known as nerve: namely, the property of stretching to a considerable extent when tension is exerted upon it, and returning to its original dimensions when the tension is released. This property renders suchsheets, which I shall call rubbery" sheets, particularly useful in the manufacture of shatter-proof glass.

l br the manufacture of cast films or sheets,

the polyvinyl acetal resin and tetrahydrofurfuryl.

oxalate may be dissolved" in a suitable solvent or solvent mixture, such, for instance, as acetone, methanol, acetone-methanol mixtures, ethylene chloride-methanol mixtures, etc., about 300 to 500 or more parts of. the solvent or solvent mixture Still another object is to being used per 100 parts of theresin. From about 2 to '100 parts or more of tetrahydrofurfuryl oxalate per 100 parts of resin may be employed,

depending upon the nature of the resin and the purpose for which the sheets are to be used. Suitable proportions of tetrahydrofurfuryl oxalate for any resin and any purpose may be readily determined by experiment. For the manufacture of sheets suitable for photographic film base, from 2 to 25 parts of tetrahydrofurfuryl oxalate per 100 parts of resin are suitable. The resin solution is cast as a sheet, the solvent evaporated, and the sheet stripped from the. casting surface.

Sheets for use in laminated glass may be formed by casting, or may be made without the use of volatile solvent by extrusion, for example inthe manner set forth in application Serial No. 147,934 of John S. Kimble and Ernest C. Blackard, filed June 12, 1937. For instance, 50 to "15 or more parts of tetrahydrofurfuryl oxalate and '100 parts of a polyvinyl .acetaldehyde or formaldehyde acetal resin may be mixed in a suitable, jacketed mixer at a low temperature, for example 10 0., and the mixture may then be worked on hot rolls, in the manner describedin U. S. Patent 2,048,686. of F. R. Conklin, until complete homogenization has taken place. The mass thus produced may then be extruded through an annular die, and the tube so formed slit to form a sheet. When the resin used.is a polyvinyl formaldehyde acetal resin, it will usually befound necessary to use or more parts of tetrahydrofurfuryl oxalate per parts of resin.

gThe polyvinyl acetal resins can be prepared by reacting polyvinyl alcohol with an aldehyde in the presence of an acetal condensation catalyst,

prepared by simultaneously de-esterifying a poly vinyl aliphatic ester and reacting the de-esterifie, g. a, mineral acid. These resins can also be 3 cation product with an aldehyde in the presence of ade-esterifying catalyst and acetal condensation catalyst; Mineral acids are catalysts for both de-esterification and acetal formation. Among the polyvinyl acetal resins with which tetrahydrofurfuryl oxalate is useful may be mentioned, as illustrative. examples, the polyvinyl formaldehyde acetal resins, the polyvinyl acetaldehyde acetal resins, the polyvinyl formaldehyde acetaldebyde mixed acetal resins, the polyvinyl butyraldehyde acetal resins,- and the polyvinyl butyraldehyde acetaldehyde mixed acetal resins. Examples of the preparation of polyvinyl formaldehyde acetal resins may be found in U. S. Patent 1,955,068, Examples 1, 4: and 5; in U. S;

' and 7; in British Patent 404,279, Example 3'; and

'paraldehyde and lbs. of HCl.

Patent 2,036,092, Examples 1, 2, 3,!7 and a; in British Patent 454,691, Examples 11' 2, 3, 4, 5, 6

in British Patent 436,072, Examples 1, 2, 3, 4, 5, 6 and 7.

A further example of the preparation of a polyvinyl formaldehyde acetal resin is as follows:

25 lbs. of polyvinyl acetate, the viscosity of whose "molar solution (86.08 g. per liter), in benzene was 45 centipoises, wasdissolved in 75 lbs. of 70% acetic acid. To this solution were added 56 grams of hydroxylamine hydrochloride, for stabilizing the resin, 5.25 lbs. of -trloxymethylene, and 6.25 lbs. of 35% 'HCl. The reaction mixture was allowed to stand for 5 days at C., after which'it was diluted with acetic acid. The resin was precipitated by pouring into cold water, washed, and dried. Analysis showed the resin to have an acetate group content equivalent to 10.6% by, weight of polyvinyl acetate and a hydroxyl group content equivalent to 7.1% by weight of polyvinyl alcohol. The stabilization of. polyvinyl acetal resins by hydroxylamine is claimed in the application of Joseph B. Hale, Serial No. 149,916, filed 'June- 23, 1937, Patent No. 2,146,735. g

Examples of the preparation of polyvinyl acetaldehyde acetal resins may be found in U.-S. Patent 2,044,730, Example 1;- U.-S. Patent 1,955,-

068, Example 2; U. S. Patent 2,036,092, Examples f polyvinyl 'acetaldehyde acetal resins are as follows:

100.lbs. of polyvinyl acetate, the viscosity of whose molar solution inbenzene was centipoises, was dissolved in 300 lbs. of 95% ethyl alcohol. To this solution were added 30 lbs. of

The reaction mixture was allowed to stand for 4 days at 40 0., after which it was diluted 'th ethyl alcohol, and the resin precipitated by pouring into cold water, washed and. dried. Analysis showed the resin to have an acetate group content equivalent to 2.1% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 12.9% by weight of polyvinyl alcohol.

25 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in 75 lbs. of 95% ethyl alcohol. To this solution was added '8 lbs. of paraldehyde and a solution, of 3 lbs. 12 ozs. oi sulfuric acid in 3 lbs. 12 czs. of 95% ethyl alcohol. The reaction mixture was allowed to stand for 7 days at 40 C., after which it was diluted with ethyl alcohol, and the resin precipitated by pouring into cold water, washed, and dried. Analysis showed the resin to have an acetate group content equivalent to l.7%-by weight of polyvinyl acetate and a hydroxyl group content equivalent to 13.8% by weight of polyvinyl alcohol. 1

lbs. of polyvinyl acetate, the viscosity of whosemolar solution in benzene was 45 centipoises, was dissolved in a mixture composed of 50 lbs. of 95% ethyl alcohol and 90 lbs. of ethyl ing into cold water. washed and dried. Analysis showed the resin to have an acetate group content-equivalent to 3.3% of polyvinyl acetate and a hydroxyl group content equivalent to 6.5% of polyvinyl alcohol.

Examples of the preparation of polyvinyl form'- aldehyde acetaldehyde' mixed acetal resins may be found in British Patent 430,136, Examples 1, 2, 3, 4, 5 and 6; British-Patent 445,565, Example 2; British Patent 465,873, Examples 1, 2, 3, 4, 5 and 6; French Patent 808,586, Examples 1, 2, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18 and 19.

Additional examples of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resins are given in the application of Ralph H. Talbot, Serial No. 85,960, filed June 18, 1936, as follows:

"Example 1 .100 parts (1.16 mol. calculated as monomeric vinyl acetate) of a polyvinyl acetate (45 centl-,

poises), 100'parts of ethyl alcohol, 180 parts of ethyl acetate, 34 parts- (.77.mol. as monomeric acetaldehyde). of paracetaldehyde and 5.8 parts (.196 mol. as monomeric formaldehyde) of paraformaldehyde were-placed in an enameled vessel and brought into solution by stirring. When solution was complete, 10 parts of sulfuric acid (sp. g'. 1.84) in lo'parts of water were added, and

the mixture stirred. The mixture was maintai'ned at a temperature of 40 C. for 144 hours. The contents of the vessel were then diluted with about two and a half volumes of acetone, and the mixture precipitated into water. The precipitated resin was washed free from impurities by repeated changes of cold water, and dried.

The resin, when analyzed, gave. ahydroxyl group content equivalent to about 6.4 per cent by weight of polyvinyl alcohol, an acetate group content equivalent to about 4.0 per cent by weight of polyvinyl acetate, a formaldehyde acetal group content equivalent to about 15.9 per cent by weightmf polyvinyl formaldehyde acetal and an acetaldehyde acetal group content equivalent to about 73.9 per cent by weight of, polyvinyl acetaldehyde acetal. The polyvinyl acetal portion of the resin was therefore made up of about 19.7 per cent by moles of polyvinyl formaldehyde acetal and about 80.3 per cent by moles of polyvinyl acetaldehyde acetal. The resin was soluble in acetone to an extent which permitted coating a film or sheet from the resin.

"Example 2 "SD-parts (.53 mol. as monomer) of polyvinyl acetate (45 centipoises) 50 parts of ethyl alcohol, 90 parts of ethyl acetate, 17 parts (.385 mol. as

-monomer) of paracetaldehyde, 2.9 parts (.098

mol. as monomer) of paraformaldehyde, 5 parts of sulfuric acid and 5 parts'of water were treated as in Example 1 for 161 hours. The well washed and dried resin gave upon analysis ahydroxyl group content equivalent to about 9.6% by weight of polyvinyl alcohol, an acetate group content equivalent to about 4.1% by weight of polyvinyl acetate, a formaldehyde acetal group content equivalent to about 13.9 per cent by weight of polyvinyl formaldehyde acetal, and an acetaldehyde acetal group content equivalent to about 69.9 per cent of polyvinyl acetaldehydefacetal. The polyvinyl acetal Portion of the resin was therefore made up of about 18.5 percent by moles of polyvinyl formaldehydeacetal and 81.5 per which permitted coating a film or sheet from the resin.

Example 3 "1300 parts (15.1 mol. as monomer) of a polyvinylacetate (45 centipoises), 1700 parts of ethyl acetate, 2250 parts of ethyl alcohol (95%) and 48 parts (1.57 mol. as monomer) of paraformaldehyde (trioxymethylene) were placed in a vessel equipped with a reflux condenser and a means of agitation, and the contents brought to a temperature of about C. by means of steam heating. 182.25 parts of sulfuric acid (sp. g. 1.84) dissolved in 51.5 parts of water were added, and the whole was heated at about 70 C. for about five hours, agitating throughout. At this point, 266.4 parts (6.05 mol. as monomer) of paracetaldehyde were added and heating at about 70 C. with agitation was continued for a further period of twenty hours. The contents of the reaction vessel were neutralized 'with ammonium hydroxide and diluted with water precipitating the resin as a cake. The cake was cut into small pieces and repeatedly washed with hot water until the resin was free from solvents, salts and other impurities. The resin, upon analysis, showed a hydroxyl group content equivalent to about 10.1 per cent by weight of polyvinyl alcohol,- an acetate group content equivalent to about 3.2 per cent by weight of polyvinyl acetate, the remainder of the weight of the resin being polyvinyl acetal. The polyvinyl acetal portion of the resin was made up of about per cent by moles of polyvinyl acetaldehyde acetal and about 20 per cent by moles of poll formaldehyde acetal. The resin was not quite soluble in acetone, but could be made to dissolve by admixing small amounts of other solvents, such as alcohols, with the acetone.

Examples of the preparation of polyvinyl butyraldehyde acetal resins may be found in U. S. Patent 2,044,730, Examples 2, 5 and 6; British Patent 466,598, ple 5; French Patent 313,303, Example 1; French Patent 813,514, Ex-

amples ll, 2, 3 and 4; and British Patent 459,878,

mamples 1, 2, 5, 6, 7,8, 9 and 10.

An additional example of the preparation of a polyvinyl butyraldehyde acetal resin is as follows:

20 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in 20 lbs. of ethyl alcohol and 36 lbs. of ethyl acetate. To this solution was added 13 lbs. of butyraldehyde and a. solution of 2 lbs. of sulfuric acid in 2 lbs. of water. The reaction mixture was allowed to stand for 8 days at 40 C., after which it was diluted with acetone, and the resin precipitated by pouring into cold water, washed and dried. Analysis showed the resin to have an acetate group content equivalent to 7.8% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 4.8% by weight of polyvinyl al-' cohol. An example of the preparation of a polyviny butyraldehyde acetaldehyde mixed acetal resin is given in French Patent 813,303, Example 2.

What I claim as my invention and-desire to be secured by Letters Patent of the United States 15:

1. A composition of matter comprising a polyvinyl acetal resin and tetrahydrofurfuryl oxalate as a plasticizer therefor.

2. A transparent, flexible sheet comprising parts of a polyvinyl acetal resin and from 2 to 25 parts, approximately, of tetrahyd'rofurfuryl oxalate as a plasticizer therefor.

3. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetal resin in which a predominating proportion of the acetal groups are selected from the group consisting of form aldehyde acetal groups and acetaldehyde acetal groups, and at least 50 parts, approximately, of tetrahydrofurfuryl oxalate as an elasticizer therefor.

4. A composition of matter comprising a polyvinyl acetaldehyde acetal resin and tetrahydrofurfuryl oxalate as a plasticizer therefor.

5. A transparent, flexible sheet comprising 100 parts of a polyvinyl acetaldehyde acetal resin and from 2 to 25 parts, approximately, of tetrahydrofurfuryl oxalate as aplasticizer therefor.

6. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetaldehyde acetal resin and at least 50 parts, approximately, of tetrahydrofurfuryl oxalate as an elasticizer therefor.

7. A composition. of matter comprising apolyvinyl formaldehyde acetal resin and tetrahydrofurfuryl oxalate asa. plasticizer therefor.

8. A transparent, rubbery sheet comprising 100 parts of a polyvinyl formaldehyde acetal resin and'at least 75 parts, approximately, of tetrahydrofurfuryl oxalate as an elasticizer therefor.

. HENRY B. SMITH. 

